Related Experiment Video
Updated: Jul 18, 2026

Monitoring ER/SR Calcium Release with the Targeted Ca2+ Sensor CatchER+
Published on: May 19, 2017
Redundant functions of RIM1alpha and RIM2alpha in Ca(2+)-triggered neurotransmitter release
Susanne Schoch1, Tobias Mittelstaedt, Pascal S Kaeser
1Emmy Noether Research Group, Institute of Neuropathology, Department of Epileptology, University Bonn, Sigmund Freud Strasse 25, 53105 Bonn, Germany. susanne.schoch@uni-bonn.de
Abstract:
Alpha-RIMs (RIM1alpha and RIM2alpha) are multidomain active zone proteins of presynaptic terminals. Alpha-RIMs bind to Rab3 on synaptic vesicles and to Munc13 on the active zone via their N-terminal region, and interact with other synaptic proteins via their central and C-terminal regions. Although RIM1alpha has been well characterized, nothing is known about the function of RIM2alpha. We now show that RIM1alpha and RIM2alpha are expressed in overlapping but distinct patterns throughout the brain. To examine and compare their functions, we generated knockout mice lacking RIM2alpha, and crossed them with previously produced RIM1alpha knockout mice. We found that deletion of either RIM1alpha or RIM2alpha is not lethal, but ablation of both alpha-RIMs causes postnatal death. This lethality is not due to a loss of synapse structure or a developmental change, but to a defect in neurotransmitter release. Synapses without alpha-RIMs still contain active zones and release neurotransmitters, but are unable to mediate normal Ca(2+)-triggered release. Our data thus demonstrate that alpha-RIMs are not essential for synapse formation or synaptic exocytosis, but are required for normal Ca(2+)-triggering of exocytosis.
More Related Videos
13:40Live Cell Calcium Imaging Combined with siRNA Mediated Gene Silencing Identifies Ca2+ Leak Channels in the ER Membrane and their Regulatory Mechanisms
Published on: July 7, 2011
12:01Acute Dissociation of Lamprey Reticulospinal Axons to Enable Recording from the Release Face Membrane of Individual Functional Presynaptic Terminals
Published on: October 1, 2014
Related Concept Videos
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Feedback Regulation of Calcium Concentration
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
IP3/DAG Signaling Pathway
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Rab Cascades
Rab Proteins
Rab proteins switch between a cytosolic, GDP-bound inactive state and a membrane-anchored, GTP-bound active state. By themselves, Rabs show slow rates of GDP/GTP exchange and GTP hydrolysis. Thus, Rab proteins are considered...